Malaysia’s ‘fish hunters’ target invasive species, one catch at a time

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Puchong, Malaysia – On a caller Sunday morning, astir a twelve men with sportfishing nets skirted the rubbish-strewn banks of the Klang River conscionable extracurricular the Malaysian superior of Kuala Lumpur.

Surveying the river, the men formed their nets into the polluted water. The nets billowed unfastened and sunk rapidly nether the value of metallic chains.

From wherever they stood connected the riverbank, they started to propulsion successful their nets, already filled with dozens of squirming black-bodied catfish.

“You don’t spot immoderate different fish. Only these,” said Mohamad Haziq A Rahman, the person of Malaysia’s “foreign food huntsman squad”, arsenic they emptied their drawback of wriggling suckermouth catfish into piles, distant from the river.

None of the food caught that greeting were sold astatine adjacent markets oregon nutrient stalls. The sole intent of the expedition was to cull suckermouth catfish, 1 among a increasing fig of invasive taxon that person successful caller decades dominated freshwater habitats crossed Southeast Asia.

Once brought successful for commercialized oregon hobbyist reasons, invasive food are not lone threatening to borderline autochthonal taxon retired of the nutrient concatenation successful Malaysia and elsewhere, but they besides dispersed diseases and origin large harm to section environments.

Invasive food are a occupation the satellite over, but experts accidental the contented is keenly felt successful mega-biodiverse Malaysia.

“More than 80 percent of rivers successful the Klang Valley person been invaded by overseas food species, which tin origin the extinction of the rivers’ indigenous aquatic life,” said Dr Kalithasan Kailasam, a stream adept with the Malaysia-based Global Environment Centre.

“It’s increasing successful astir each different main rivers successful Malaysia,” said Kailasam, explaining however taxon specified arsenic the suckermouth person the imaginable to rapidly reproduce and past successful soiled water, leaving section food connected the losing side.

Aside from the suckermouth, Malaysia’s waterways are present threatened by taxon specified arsenic the assertive peacock bass, Javanese carp and redtail catfish, helium said.

While the afloat grade of the occupation is not yet known, Malaysia’s fisheries department, aft a four-year survey until 2024, recovered invasive taxon successful 39 areas crossed astir each authorities successful peninsular Malaysia and connected the land of Labuan, including successful dams, lakes and large rivers.

Alarmed by the threat, a tiny radical of citizens banded unneurotic to combat the aquatic invaders.

Led by Haziq, they are moving to reclaim Malaysia’s rivers 1 fin astatine a time.

Invasive food invasion

The national food hunters’ quest to combat invasive taxon started during the country’s COVID-19 lockdowns, erstwhile Haziq, a erstwhile healthcare consultant, turned to sportfishing arsenic a pastime successful a stream adjacent his location successful cardinal Selangor state. He recovered each food helium caught was of the suckermouth variety, besides known arsenic the “pleco” oregon “ikan bandaraya” – which translates arsenic the “janitor fish” successful Malay and is favoured by hobbyists to support aquariums clean, arsenic the suckermouth feeds connected algae, leftover nutrient and dormant fish.

Native to South America, varieties of the suckermouth person besides been introduced into waterways successful the United States, Bangladesh, and Sri Lanka, often erstwhile owners dump them into rivers, canals, dams oregon escaped them aft they turn excessively ample for their aquarium tanks.

Because of their thick, scaly skin, suckermouths are usually avoided by adjacent larger predators successful Malaysia, and tin turn to astir fractional a metre (1.6ft) successful length.

As bottommost feeders, the catfish person been known to devour the eggs of different taxon and destruct their nesting sites. Catfish besides burrow into riverbanks to nest, causing them to erode and collapse, which is simply a superior biology contented successful flood-prone Malaysia wherever year-end monsoon winds bring dense rain.

Malaysia’s cardinal slope said successful 2024 that floods are the origin of 85 percent of the country’s earthy disasters, with their frequence expanding since 2020.

Though acold from his favourite food to catch, Haziq discovered that suckerfish roe could beryllium utilized arsenic bait for different bigger fish, and helium earned immoderate wealth selling their eggs to different sportfishing enthusiasts. He besides gained a pursuing by putting his exploits connected societal media. Further probe past led him to larn astir the threats posed by invasive species.

Harziq started to pull like-minded anglers, and, successful 2022, they decided to signifier a radical for hunting suckermouth, gathering astir each week successful a stream to transportation retired a cull.

Their nationalist illustration and popularity are growing. The group’s rank has present grown to much than 1,000, and it has a beardown instrumentality pursuing connected societal media.

“People kept asking however to articulation our group, due to the fact that we were looking astatine the ecosystem,” Haziq said.

Focusing archetypal connected Malaysia’s Selangor authorities and rivers successful the superior Kuala Lumpur, the food huntsman squad netted astir 31 tonnes of suckermouths unsocial successful 2024. They person besides visited rivers successful different states successful Malaysia arsenic their run expands.

Dispose, usage for research, oregon navigator and eat?

During a hunt successful the Klang River earlier this year, Haziq and his comrades deployed to the river’s banks connected a ngo to spot however galore suckermouth they could drawback during a azygous outing.

But hunting for invasive food tin beryllium tricky. Without boats, the hunters person to wade into the fast-moving polluted waters from muddy banks, portion navigating underwater debris specified arsenic rubbish connected the riverbed.

Almost each the food they caught were of the invasive kind, but erstwhile successful a while, they bash nett a local.

“Haruan (snakehead)!” shouted ex-navy diver Syuhaily Hasibullah, 46, arsenic helium showed disconnected a tiny food fractional the size of his arm, taken from a nett containing respective suckermouths.

“This 1 is rare! There utilized to beryllium a batch of them successful the river,” helium told Al Jazeera.

Haziq said if the hunters recovered galore invasive taxon successful their nets, they would organise different outing to the aforesaid location, bringing on much radical to instrumentality part.

The time they acceptable retired to cipher however galore invasive food they could drawback successful a azygous outing turned retired to output fractional a tonne of suckermouth successful conscionable 3 hours – truthful galore they had to worldly them into sacks.

Previously, the hunters buried their hauls successful heavy holes distant from the river. Now, they person recovered much originative ways to dispose of what is, generally, an unwanted fish.

At the lawsuit earlier this year, sacks of suckermouths were handed implicit to a section entrepreneur looking to experimentation with turning the food into a signifier of charcoal known arsenic biochar.

Some section universities person besides started researching the imaginable usage of the suckermouth. One assemblage probe nonfiction explored the imaginable of suckermouth collagen for pharmaceutical use, portion different considered its usage arsenic fertiliser oregon adjacent arsenic a benignant of leather.

On immoderate occasions, the hunters adjacent devour the food they catch, though that depends connected which stream they person been taken from.

While redtail oregon African catfish are considered delicacies by some, the suckermouth, besides known successful India arsenic “devil fish”, is simply a little charismatic snacking enactment – but not retired of the question erstwhile it comes to a speedy riverside grill.

“If the food is from the Klang River, we don’t devour it,” Mohd Zulkifli Mokhtar told Al Jazeera, earlier dozens of hunters broke their accelerated during the beatified Muslim period of Ramadan.

“But if it’s from the Langat River, it’s inactive OK,” Zulkifli said, arsenic dozens of suckermouth caught successful the little polluted Langat River, located successful Bangi immoderate 25km (16 miles) southbound of Kuala Lumpur, were gutted, marinated successful satay and grilled connected skewers.

Studies from Bangladesh and Indonesia person recovered varieties of catfish with precocious levels of dense metals and contaminants. A 2024 nonfiction by Malaysia’s Universiti Teknologi Mara cited a survey that showed the level of contaminants successful the suckermouth was “heavily influenced by the level of contamination successful the river”.

‘If we don’t enactment now, it would beryllium worse’

While Malaysia’s fisheries section said determination were nary records of section taxon becoming endangered due to the fact that of invasive ones, autochthonal food nevertheless look threats.

Local food either faced becoming prey oregon person had to combat to survive, with the section uncovering successful a survey that 90 percent of the food successful six rivers successful the Selangor and Kuala Lumpur portion were present overseas arrivals.

The department’s Director-General Adnan Hussain said assorted measures had been enactment successful place, including the merchandise of immoderate 33.6 cardinal autochthonal food and prawns into rivers nationwide from 2021 to 2025 to “balance the impact” of invasive fish.

Late past year, the authorities authorities of Selangor besides came up with a strategy to wage anglers 1 Malaysian ringgit ($0.23) for each kilogramme (2.2lb) of the suckermouth food removed from 2 rivers. The captured food were to beryllium turned into carnal provender and integrated fertiliser, an authoritative said.

Restrictions connected the import of definite overseas aquatic taxon – including full taxon and groups – into Malaysia were besides imposed past year, and helium added that programmes and collaboration with the food hunters had besides helped to woody with the problem.

In 1 stream successful Selangor state, Adnan said the magnitude of invasive food caught pursuing 1 eradication programme had dropped from 600kg (1,300lb) successful a May 2024 lawsuit to conscionable much than 150kg (330lb) 4 oregon 5 months later.

However, Universiti Malaysia Terengganu food researcher Professor Amirrudin Ahmad said it was “almost impossible” to afloat exterminate the country’s invasive fish.

“So galore taxon unrecorded successful (native h2o bodies) and getting escaped of invasive taxon by the means of poisoning the h2o is not feasible astatine all,” helium said, adding determination were adjacent to 80 recorded food taxon introduced successful Malaysia truthful far.

He further warned that rising temperatures caused by clime alteration whitethorn adjacent let taxon similar the predatory Mekong redtail catfish to proliferate successful cooler upstream waters successful Malaysia.

“They are present to stay,” Amirrudin said.

“It is simply,” helium said, “that the situation is mostly akin to their autochthonal country, oregon these taxon are highly adaptable.”

That this is an ecological warfare that tin ne'er genuinely beryllium won is simply a constituent that Haziq and his chap food hunters are afloat alert of. Nearly each stream they visited successful caller times had astir thing but invasive fish, helium said.

But their ngo volition transportation on, helium added, on with the hunting and nationalist consciousness that has spurred thousands to travel his societal media videos connected the subject.

“Yes, this food won’t beryllium wholly gone from our rivers,” helium told Al Jazeera.

“But if we don’t enactment now, it would beryllium worse,” helium said.

“It’s amended to instrumentality enactment than to conscionable permission it alone,” helium added.

“At slightest we tin trim the population, than let it to wholly instrumentality implicit our section fish.”

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